Metastable ion decomposition and collisional activation mass spectra of 1,2,3‐triarylpropen‐1‐ones

Substituents have been found to have a marked influence on the metastable ion decompositions and collisionally activated (CA) fragmentations of the M+˙ ion of a number of 1,2,3-triarylpropen-1-ones. An attempt has been made to confirm the structures of the rearrangement ions, [C14H10]+˙, [C13H11]+˙, [C13H9]+ and [C12H8]+˙ by comparison of their CA spectra with those of the corresponding ions produced from reference compounds. The results imply that [C14H10]+˙ and the M+˙ ions of phenanthrene and diphenylacetylene have a common structure, [C13H9]+ and the fluorenyl cation have a common structure and [C12H8]+˙ and biphenylene molecular ion have a common structure. The available data indicate that the ion at m/z 167 consists of a mixture of structures, likely possibilities being diphenylmethyl, phenyltropylium and dihydrofluorenyl cations.